Computer platforms used for commercial applications typically operate in an environment where their behaviour is vulnerable to modification by local or remote entities.
Additionally, with the continuing increase in computer power it has become increasingly common for computer platforms to support multiple users, where each user can have their own operating environment installed on the computer platform.
The operating system software typically runs at the system privilege level of a processor, where the system privilege level permits the individual operating systems to utilise both privileged and non-privileged instructions provided by the processor hardware. As such, where a number of separate operating systems are running simultaneously on a computer platform the operating systems are sharing full system privilege and are not necessarily isolated or protected from one another. The volume of source code for software components sharing full system privilege is typically so large in modern operating systems that it is virtually impossible to ensure the correctness of the source code and whether the behaviour of the source code will behave as expected.
Accordingly, this potential insecurity of the platform is a limitation on its use by parties who might otherwise be willing to use the platform.
Increasing the level of trust in platforms therefore enables greater user confidence that the platform and operating system environment behave in a known manner.